In the field of video surveillance, it is desired to provide the maximum amount of surveillance of the secured area with the minimum amount and complexity of security camera equipment. Television security cameras are often mounted in fixed positions at locations which provide the greatest possible viewing area per camera. When corridors intersect, it is common practice to install two or more cameras in fixed positions at the intersection, with each camera pointed towards a different corridor. In addition, when a long corridor must be monitored, it is common to utilize multiple cameras in fixed positions at various points thereof.
In order to monitor each of the images from the various cameras, it is necessary to provide means for switching from the image provided by one camera to the next. Alternatively, multiple video monitors can be used, corresponding to the number of cameras in the system. Both these methods of monitoring the large number of images provided by the various fixed point cameras are, however, costly.
An alternative way to provide greater coverage is to provide a security camera with means for panning the area under surveillance, rather than fixing the camera in one position. To accomplish this, servo motor drive assemblies are implemented with automatic pan or remote control mechanisms. Typically, a security guard located at a strategically located guard station will operate such remote control devices.
In addition, numerous devices exist in the prior art which operate to move assemblies of mirrors and prisms in order to provide a fixed position security camera with greater surveillance capability. Such mechanisms are also costly and must be aligned and serviced in order to maintain the needed reliability.
Although the use of automatic or semi-automatic drive assemblies enables the reduction of the number of security cameras and corresponding monitors, such assemblies are costly to install and maintain. Moreover, the chance of failure of mechanical panning devices is considerably detrimental in high security applications. Further, the use of such prior art techniques provide only one view for transmission to a monitor at any given time.
Accordingly, it is an object of the present invention to provide video surveillance of a large area with minimal cost and chance of failure.
It is a further object of the present invention to enable a security camera to monitor optical images from two directions simultaneously, thus eliminating the need for mechanical devices which scan areas of a geometrical size too large or of too complex a structure for one security camera to capture.
It is a further object of the present invention to provide an attachment for a standard commercially available security camera to generate separate images of different areas for simultaneous display on a standard commercially available monitor without additional electronic modifications thereto.